Solid inkjet imaging systems generally use an electronic form of an image to distribute ink melted from a solid ink stick or pellet in a manner that reproduces the electronic image. In some solid inkjet imaging systems, the electronic image may be used to control the ejection of ink directly onto a media sheet. In other solid inkjet imaging systems, the electronic image is used to operate printheads to eject ink onto an intermediate imaging member. A media sheet is then brought into contact with the intermediate imaging member in a nip formed between the intermediate member and a transfer roller. The heat and pressure in the nip help transfer the ink image from the intermediate imaging member to the media sheet, which is transported from the system and deposited in a paper tray.
In solid ink imaging systems having intermediate imaging members, ink is loaded into the system in a solid form, either as pellets or as ink sticks, and transported through a feed chute by a feed mechanism for delivery to a melting device. The melting device heats the solid ink to its melting temperature and the liquid ink is delivered to a printhead for jetting onto an intermediate imaging member. In the print head, the liquid ink is typically maintained at a temperature that enables the ink to be ejected by the printing elements in the print head, but that preserves sufficient tackiness for the ink to adhere to the intermediate imaging member. In some cases, however, the tackiness of the liquid ink may cause a portion of the ink to remain on the intermediate imaging member after the image is transferred onto the media sheet and the residual ink may later degrade other ink images formed on the intermediate imaging member.
To address the accumulation of ink on an intermediate imaging member, which may be in the form of a drum, solid ink imaging systems may be provided with a drum maintenance unit (DMU). In solid ink imaging systems, the DMU is configured to 1) lubricate the image receiving surface of the intermediate imaging member with a very thin, uniform layer of release agent before each print cycle, and 2) remove and store any excess release agent, ink and debris from the surface of the intermediate imaging member after each print cycle. During each print cycle, the release agent deposited on the intermediate imaging member may be controlled with a flexible metering blade. The metering blade is designed to distribute release agent on, and possibly remove excess release agent from, the intermediate imaging member so the release agent does not degrade the media sheet in the nip.
Metering blades wear over time, causing excess release agent or an uneven layer of release agent on the intermediate imaging drum. An incorrect or inconsistent amount of release agent applied to the surface of the intermediate imaging drum may result in some of the solid ink adhering to the imaging drum or in excess release agent being transferred to the media. The consequences of problems in forming the release agent layer may produce print quality defects, such as smudging or poor image fixation. Preservation of the components for metering release agent and cleaning the imaging surface in a solid ink printer is desirable.